FBI agents hunting for last year’s anthrax-sending psycho searched a Florida storage trailer belonging to a bioresearch scientist who three years ago commissioned a study into ways the deadly bacteria can be delivered by mail.

Federal sources said the scientist, Dr. Steven Hatfill of Hagerstown, Md., is a “person of interest” in their probe into the deadly wave of mailings that killed five people last fall.

They caution, however, that Hatfill is one of about 30 individuals the bureau is closely scrutinizing because of their specialized knowledge and because they may have had access to the deadly biological toxin.

On Wednesday, agents searched a storage facility in Ocala used by Hatfill to store personal belongings after his parents sold a nearby farm.

Ocala is about 230 miles northwest of Boca Raton, where Robert Stevens, the photo editor of a tabloid newspaper, was killed by a letter containing anthrax.

In another coincidence, Hatfill once asked a bioterrorism expert to do a study into how anthrax could be spread by mail while he worked as a researcher for defense contractor Science Applications International.

A report in The Sun of Baltimore said the study revealed how 2½ grams of bacillus globigii, a simulated form of anthrax, could be mailed in a standard business envelope.

Ben Hadad, a spokesman for the San Diego-based company that Hatfill worked for, said the researcher and another employee commissioned the report in February 1999 as part of the company’s official business. Hadad said there was nothing unusual about the commission, but would not release the report.

Hatfill is one of about 200 people the FBI has investigated in the wake of last year’s mailing. Investigators still have no firm suspect.

Yet another coincidence, however, has led them to probe Hatfill, who has voluntarily allowed his Maryland apartment and Florida trailer to be searched.

The coincidence relates to his medical alma mater, the University of Zimbabwe Medical School.

The school is located in the Greendale neighborhood of Zimbabwe’s capital, Harare.

Hatfill could not be reached for comment yesterday, but has protested his innocence in the past.

“I’ve been in this field for a number of years, working until 3 o’clock in the morning, trying to counter this type of weapon of mass destruction, and, sir, my career is over at this time,” Hatfill said. With Post Wire Services